Oral care compositions

ABSTRACT

Oral care composition comprise a stannous ion source and a thickener consisting essentially of carrageenan and xanthan gum. A method for treating the oral cavity comprises administering the composition to the oral cavity in a toothpaste.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of Application No. CN2014/076944filed May 7, 2014.

FIELD OF THE INVENTION

The present invention relates to oral care compositions containingstannous ions.

BACKGROUND OF THE INVENTION

Tin (II) (stannous) ions (i.e., stannous chloride) are added to oralcare compositions to deliver multiple benefits including, for example:anti-microbial effects, control of breath malodor, control of dentalplaque growth and metabolism, and reduced gingivitis. However, oral carecompositions containing stannous chloride, especially in combinationwith thickening agents such as carboxymethyl cellulose (CMC), can sufferfrom poor rheological properties.

One of the main reasons for the problem is that Sn²⁺ ion is prone tooxidation towards Sn⁴⁺ causing the oral care composition to exhibit anunacceptably low viscosity. If a formulation routinely decreases inviscosity, such oral care composition can lack phase stability and tendsto undergo phase separation over time or physical degradation of thestructure. The problem is especially noticeable at the tip of thedispenser due to higher levels of oxygen penetrating the container fromthe exterior and reacting with the oral care composition closest to thetip.

As a result, consumer dissatisfaction will likely result as the oralcare composition nearest the tip will be dispensed first from thedispenser and appear watery as the liquid has separated from the body ofthe composition. Various formulation approaches have been tried tostabilize stannous chloride containing oral care composition. PCTPublication No. WO2008/41055 (P&G) discloses stannous chloridecontaining oral care compositions. The composition examples includecarboxymethyl cellulose (CMC). PCT Publication No. WO2010/114546(Colgate-Palmolive) discloses dentrifice compositions comprisingpolysaccharide thickeners having xanthan gum and hydroxyethyl cellulose(HEC) for decreasing the viscosity of the toothpaste.

Despite the foregoing, there is still a need for stannous ionscontaining oral care compositions having improved phase stability and/orshelf-life stability over time (greater than 4 months to 24 months), atambient conditions.

SUMMARY OF THE INVENTION

In one aspect, the present invention is directed to oral carecompositions comprising: (a) from 0.01% to 5% of a stannous ion; (b) athickener consisting essentially of: i) a carrageenan; and ii) a xanthangum; and (c) at least 30% of a total water content; wherein the oralcare composition has a pH of greater than 4 and is substantially free ofa charged cellulose derivative having greater than 0.5 charged groupsper sugar residue unit along the polysaccharide backbone. This minimizescost and complexity to the formulation.

In another aspect, the present invention relates to a method fortreating the oral cavity comprising administering to the oral cavity anoral care composition as described herein above.

One aim of the present invention is to provide an oral care composition,as described herein above, which can exhibit good rheologicalproperties.

Another aim of the present invention is to provide such an oral carecomposition, as described herein above, with robust ‘Tip Viscosity’which permits the composition to exhibit sufficient phase stability suchthat it does not phase separate after 4 months, preferably after 6months, more preferably after 12 months, or even more preferably after24 months, at ambient conditions.

A further aim of the present invention is to provide such an oral carecomposition, as described herein above, without a significant variationin the ‘Tip Viscosity’ of the oral care composition after 4 months,preferably after 6 months, more preferably after 12 months, or even morepreferably after 24 months, at ambient conditions.

A yet further aim of the present invention is to provide such an oralcare composition, as described herein above, which tends not to exhibitsubstantial decreases in ‘Tip Viscosity’ after 4 months, preferablyafter 6 months, more preferably after 12 months, or even more preferablyafter 24 months, at ambient conditions.

These and other features, aspects, and advantages of the presentinvention will become evident to those skilled in the art from thedetailed description which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims that particularly pointout and distinctly claim the invention, it is believed the presentinvention will be better understood from the following description ofthe accompanying figures.

FIG. 1 is a photo of a SnCl₂ and carboxymethyl cellulose (CMC)containing oral care composition that has undergone phase separation dueto oxidation reaction.

FIG. 2 shows the Tip Viscosity over time for a sample oral careformulation of the present invention versus a comparative sample.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

As used herein, the term “average molecular weight” refers to theaverage molecular weight as determined using gel permeationchromatography according to the protocol found in Colloids and SurfacesA. Physico Chemical & Engineering Aspects, Vol. 162, 2000, pg. 107-121.Unless otherwise specified, all molecular weight values herein refer tothe weight average molecular weight and expressed in g/mol.

As used herein, the term “average degree of polymerization” (ADP) refersto the average degree of polymerization as determined by n, which refersto the number of anhydroglucose units (which are joined through 1,4glucosidic linkages in cellulose structure) or the degree ofpolymerization (DP). ADP is calculated using the protocol found inIntrinsic Viscosity and Overall Rate, Journal of Polymer Science, Vol.56, 1962, pg. 233-243.

The term “comprising” as used herein means that steps and ingredientsother than those specifically mentioned can be added. This termencompasses the terms “consisting of” and “consisting essentially of.”The compositions of the present invention can comprise, consist of, andconsist essentially of the essential elements and limitations of theinvention described herein, as well as any of the additional or optionalingredients, components, steps, or limitations described herein.

The term “oral care composition” as used herein means a product that inthe ordinary course of usage is retained in the oral cavity for a timesufficient to contact some or all of the dental surfaces and/or oraltissues for purposes of oral activity. In one embodiment, thecomposition provides a benefit when used in the oral cavity. The oralcare composition of the present invention may be in various formsincluding toothpaste, dentifrice, tooth gel, tooth powders, tablets,rinse, sub gingival gel, foam, mouse, chewing gum, lipstick, sponge,floss, prophy paste, petrolatum gel, or denture product. In oneembodiment, the oral composition is in the form of a paste or gel. Inanother embodiment, the oral composition is in the form of a dentifrice.The oral composition may also be incorporated onto strips or films fordirect application or attachment to oral surfaces, or incorporated intofloss.

The term “orally acceptable carrier” as used herein means a suitablevehicle or ingredient, which can be used to form and/or apply thepresent compositions to the oral cavity in a safe and effective manner.

The term “dentifrice” as used herein means paste, gel, powder, tablets,or liquid formulations, unless otherwise specified, that are used toclean the surfaces of the oral cavity.

The terms “phase stable” and “phase stability” are used interchangeablyand refer to the oral care composition visually (i.e., to the unaidedeye) having no liquid separation from the composition's body over adefined period of time (under ambient conditions). In other words, phasestable oral care compositions of the present invention can resistsyneresis.

The terms “shelf-life stable” and “shelf-life stability” are usedinterchangeably and refer to the oral care composition being deemedconsumer acceptable after a defined period of time after its production(under ambient conditions). The test to determine this is by invertingthe dispenser containing the oral care composition and holding itvertically for 10 seconds during which oral care composition should notdrip out of the dispenser.

The term “substantially free” as used herein refers to no intentionalamount of that material is added to the composition or an amount of amaterial that is less than 1%, 0.5%, 0.25%, 0.1%, 0.05%, 0.01%, or0.001% of the composition.

The term “teeth” as used herein refers to natural teeth as well asartificial teeth or dental prosthesis.

The term “Tip Viscosity” as used herein means the viscosity of the oralcare composition expressed in Pa·s and measured at or near the tipportion of the dispenser in which the composition is contained. The TipViscosity is determined according to the Tip Viscosity Assay asdisclosed herein in the Test Methods Section.

The term “total water content” as used herein means both free water andwater that is bound by other ingredients in the oral care composition.

All percentages, parts and ratios are based upon the total weight of thecompositions of the present invention, unless otherwise specified. Allsuch weights as they pertain to listed ingredients are based on theactive level and, therefore do not include solvents or by-products thatmay be included in commercially available materials, unless otherwisespecified.

As used herein, the articles including “a” and “an” when used in aclaim, are understood to mean one or more of what is claimed ordescribed.

As used herein, the terms “comprise”, “comprises”, “comprising”,“include”, “includes”, “including”, “contain”, “contains”, and“containing” are meant to be non-limiting, i.e., other steps and othersections which do not affect the end of result can be added. The aboveterms encompass the terms “consisting of” and “consisting essentiallyof”.

As used herein, the words “preferred”, “preferably” and variants referto embodiments of the invention that afford certain benefits, undercertain circumstances. However, other embodiments may also be preferred,under the same or other circumstances. Furthermore, the recitation ofone or more preferred embodiments does not imply that other embodimentsare not useful, and is not intended to exclude other embodiments fromthe scope of the invention.

Specifically, the present invention provides an oral care compositioncomprising:

-   -   a. from 0.01% to 5% of stannous ions;    -   b. a thickening agent consisting essentially of:        -   i) from 0.65% to 5% of a carrageenan; and        -   ii) from 0.3% to 5% of a xanthan gum; and    -   c. at least 30% of a total water content;

wherein the composition has a pH greater than 4 and is substantiallyfree of a charged cellulose derivative having greater than 0.5 chargedgroups per sugar residue unit along the polysaccharide backbone.

Stannous Ions

Stannous ions are used in oral care compositions to deliver benefitssuch as, for example, enamel care and cavity protection. Suitablestannous sources include stannous chloride, stannous fluoride, stannousacetate, stannous gluconate, stannous oxalate, stannous sulfate,stannous lactate and stannous tartrate. Preferably, the stannous salt isstannous chloride (i.e., SnCl₂) and may include stannous chloridedehydrate, stannous chloride anhydrous, and combinations thereof.Alternatively, the use a combination of stannous salts (e.g., stannouschloride and stannous fluoride) whereby both the desired stannous andfluoride ion are supplied through these salt combinations. The oral carecompositions of the present invention may contain stannous ions in theamount ranging from 0.01% to 5% (100 to 50,000 ppm), 0.05% to 4% (500 to40,000 ppm), or 0.075% to 3% (750 to 30,000 ppm). Preferably, such oralcare compositions contain from 0.1% to 2% (1,000 to 20,000 ppm), from0.5% to 1.5% (5,000 to 15,000 ppm), or from 0.2% to 0.7% (2,000 to 7,000ppm) stannous ions.

The present invention is based on the observation that oral carecompositions containing stannous ions (e.g., SnCl₂) in combination withcertain thickening agents, such as charged cellulose derivatives likecarboxymethyl cellulose (CMC), suffer from a decrease in viscosity ofthe composition near the tip of the dispenser. Over time this leads tothe liquid separating from the body of the composition and a phasestability problem (see FIG. 1). This problem is most noticeable near thetip of the dispenser because oxygen can slowly penetrate through thecrimped portions of the dispenser from the exterior and react with theunbound Sn ions in the formulation, as follows:6SnCl_(2 (aq))+O_(2 (g))+2H₂O_((l))→2SnCl_(4 (aq))+4Sn(OH)Cl_((s))

CMC is an anionic polysaccharide commonly used as a structurant materialin oral care compositions. The carboxyl group of the CMC reacts with thedivalent ions (e.g., Sn²⁺) to form cross-linked gels and providesufficient viscosity and phase stability benefits to the compositions.Without wishing to be bound by theory, it is believed that the highervalent ion (e.g., Sn⁴⁺) precipitate formed when the stannous oxidizationoccurs near the tip can inhibit the CMC gel hydration. As a consequence,the viscosity of the composition near the tip of the dispenser (referredto as ‘Tip Viscosity’) drops and the composition becomes thinner andmore watery (also known as ‘phase separation’). Applicants havesurprisingly discovered an improved thickener system, as describedherein below, for use in stannous ions containing oral care compositionsto avoid, or at least mitigate, aid to reduce and/or eliminate the TipViscosity drop and/or phase stability problem near the tip of thedispenser.

Thickening Agents

The oral care compositions herein may include one or more thickeningagents or binders to provide a number of benefits such as, for example,a desirable consistency of the oral care composition, desirable activerelease characteristics upon use, acceptable shelf-life stability(greater than 4 months to 24 months, or longer), acceptable phasestability (greater than 4 months to 24 months, or longer), and/oracceptable Tip Viscosity (greater than 100 P·s after 4.5 months at 40°C.) of the oral care composition.

Thickeners are present in the oral care compositions in the range fromabout 0.01% to about 15%, or from about 0.05% to about 10%, or fromabout 0.075% to about 7.5%. Preferably, such oral care compositionscontain from about 0.1% to about 5%, or from about 0.5% to about 3%, orfrom about 0.75% to about 2%, thickeners.

The thickeners of the present invention consist essentially of acarrageenan and a xanthan gum. In an embodiment, the carrageenan ispresent in the oral care composition in the range from 0.65% to 5%, orfrom 0.75% to 4%, or from 1% to 3%, or from 1.25% to 2%. In anotherembodiment, the carrageenan may be selected from the group consisting ofKappa-carrageenan, Iota-carrageenan, Lambda-carrageenan, andcombinations thereof. Preferably, the carrageenan is Iota-carrageenan.In another embodiment, the xanthan gum is present in the oral carecomposition in the range from 0.3% to 5%, from 0.5% to 4%, or from 0.75%to 3%.

The oral care composition of the present invention is substantially freeof a charged cellulose derivative having greater than 0.5 charged groupsper sugar residue unit along the polysaccharide backbone. In anembodiment, the oral care composition is substantially free of a chargedcellulose derivative having greater than 0.6, or greater than 0.7, orgreater than 0.8 charged groups per sugar residue unit along thepolysaccharide backbone. A specific example of such a charged cellulosederivative is carboxymethyl cellulose (CMC).

Applicants have found that the use of a thickening agent having a lowerconcentration of reactive groups (e.g., carboxylate groups) means thatthere are fewer sites for cross-linking between the thickener and thestannous ions. For example, both CMC and xanthan gum contain carboxylategroups along their backbones. However, the density of chargedcarboxylate groups along the backbone for each polysaccharide is quitedifferent. For instance, one commercially available form of CMC (CMC2000S available from CPKelco) has a degree of substitution of about 0.9carboxylate groups per sugar residue. In contrast, xanthan gum has adegree of substitution of less than 0.4 carboxylate groups per sugarresidue.

Without wishing to be bound by theory, Applicants believe the degree ofsubstitution with reactive groups has an impact on the rheology of theresultant composition. For instance, Sn²⁺ complexes with the carboxylategroups to form ionic cross-links or bridges in-between two opposingcarboxylate groups found on CMC or xanthan gum to form large networksthat can increase viscosity of the compositions. Since the loss of freeSn ions due to the oxidation reaction with O₂ and H₂O near the tip ofthe container will impact this ionic bridging and because there is lesspotential for ionic bridging for polysaccharides having less than 0.5charged groups per sugar residue, Applicants have substituted xanthangum for CMC in order to ensure robust Tip Viscosity of the compositiondespite the loss of Sn²⁺ due to oxidation.

pH

The pH of the oral care composition is greater than 4. Preferably, thepH may be between 4.5 to 9.5, more preferably from 5 to 7, alternativelygreater than 6, alternatively greater than 7, alternatively from 8 to 9,or combinations thereof. The pH is typically measured using a ratio of1:3 of paste:water. For example, whereby 1 gram of the oral carecomposition (e.g., toothpaste) is mixed into 3 grams of deionized water,and then the pH with an industry accepted pH probe that is calibratedunder ambient conditions. The pH is measured by a pH meter withAutomatic Temperature Compensating (ATC) probe. The pH meter is capableof reading to 0.001 pH unit. After each usage the electrode should bewashed free from the sample solution with water.

Remove any excess water by wiping with a tissue, such as Kimwipes orequivalent. When the electrode is not in use, keep the electrode tipimmersed in pH 7 buffer solution or electrode storage solution.Equipment details are as follows:

-   -   pH Meter: Meter capable of reading to 0.01 or 0.001 pH units.    -   Electrode: Orion Ross Sure-Flow combination: Glass body—VWR        #34104-834/Orion #8172BN or VWR#10010-772/Orion #8172BNWP.        -   Epoxy body—VWR #34104-830/Orion #8165BN or            VWR#10010-770/Orion #8165BNWP.        -   Semi-micro, epoxy body—VWR #34104-837/Orion #8175BN or            VWR#10010-774/Orion #3175BNWP.        -   Orion PerpHect combination: VWR #34104-843/Orion #8203BN            semi-micro, glass body.    -   ATC Probe: Fisher Scientific, Cat. #13-620-16.        pH Buffering Agent

The oral care compositions herein may include an effective amount of abuffering agent or pH trimming agents, as used herein, refer to agentsthat can be used to adjust the pH of the oral care compositions to theabove-identified pH range. The buffering agents include alkali metalhydroxides, ammonium hydroxide, organic ammonium compounds, carbonates,sesquicarbonates, borates, silicates, phosphates, imidazole, andmixtures thereof.

Specific buffering agents include monosodium phosphate (monobasic sodiumphosphate), trisodium phosphate (sodium phosphate tribasic dodecahydrateor TSP), sodium benzoate, benzoic acid, sodium hydroxide, potassiumhydroxide, alkali metal carbonate salts, sodium carbonate, imidazole,pyrophosphate salts, sodium gluconate, lactic acid, sodium lactate,citric acid, sodium citrate, phosphoric acid.

In one embodiment, 0.01% to 3%, preferably from 0.1% to 1% of TSP byweight of the composition, and 0.001% to 2%, preferably from 0.01% to0.3% of monosodium phosphate by weight of the composition is used.Without wishing to be bound by theory, TSP and monosodium phosphate mayhave calcium ion chelating activity and therefore provide somemonofluorophosphate stabilization (in those formulations containingmonoflurophospahte).

Water

The term “orally acceptable carrier” as used herein means a liquid orsemi-solid vehicle such as a paste or a gel for containing the activeingredients of the present invention and delivering them to the oralcavity. Water is commonly used as a carrier material in oralcompositions due to its many benefits. For example, water is useful as aprocessing aid, is benign to the oral cavity and assists in quickfoaming of toothpastes. Water may be added as an ingredient in its ownright or it may be present as a carrier in other common raw materialssuch as, for example, sorbitol and sodium lauryl sulphate. The termtotal water content as used herein means the total amount of waterpresent in the oral care composition, whether added separately or as asolvent or carrier for other raw materials but excluding that which maybe present as water of crystallization in certain inorganic salts.

The oral care compositions of the present invention comprise at leastabout 30% of a total water content. In an embodiment, the oral carecomposition comprises from about 40% to about 70% of a total watercontent. In other embodiments, the compositions include from about 45%to about 65%, alternatively from about 40% to about 60%, alternativelyfrom about 50% to about 70%, alternatively from about 50% to about 60%,alternatively from about 45% to about 55%, alternatively from about 55%to about 65%, alternatively from about 50% to about 60%, alternativelyabout 55%, alternatively combinations thereof, of a total water content.Preferably, the water is USP water.

Chelants

The oral care compositions of the present invention comprise one or morechelants, also known as chelating agents. The term “chelant”, as usedherein means a bi- or multidentate ligand having at least two groupscapable of binding to stannous ions and preferably other divalent orpolyvalent metal ions and which, at least as part of a chelant mixture,is capable of solubilising the stannous ions and other optional metalions within the oral care composition. Groups capable of binding tostannous and other metal ions include carboxyl, hydroxl and aminegroups. Typically, those chelants useful herein will also form watersoluble stable complexes with the stannous ions.

Suitable chelants herein include C₂-C₆ dicarboxylic and tricarboxylicacids, such as succinic acid, malic acid, tartaric acid and citric acid;C₃-C₆ monocarboxylic acids substituted with hydroxyl, such as gluconicacid; picolinic acid; amino acids such as glycine; salts thereof andmixtures thereof. The chelants can also be a polymer or copolymer inwhich the chelating ligands are on the same or adjacent monomer.

Preferred chelant polymers are polyacids selected from the groupconsisting of a homopolymer of a monomer, a co-polymer of two or moredifferent monomers, and a combination thereof wherein the monomer or atleast one of the two or more different monomers is selected from thegroup consisting of acrylic acid, methacrylic acid, itaconic acid,maleic acid, glutaconic acid, aconitic acid, citraconic acid, mesaconicacid, fumaric acid and tiglic acid.

Particularly preferred is a methylvinylether/maleic acid (PVM/MA)copolymer. Also suitable are tripolyphosphates. Longer chain linearpolyphosphates, though good chelants, are susceptible to hydrolysis inaqueous compositions. Upon hydrolysis they form Olihophosphates whichform insoluble zinc complexes. In one embodiment the compositioncomprises less than 0.1% of polyphosphates having a chain length of fouror more.

Preferred organic acid chelants herein comprise citrate, malate,tatirate, gluconate, succinate, lactate, malonate, maleate, and mixturesthereof, whether added in their free acid or salt forms.

Abrasives

Dental abrasives are useful in oral care compositions for their abilityto remove surface stains and pellicle and for polishing the teeth. Theoral care compositions of the present invention may contain a dentalabrasive. Dental abrasives useful in the oral care composition of thesubject invention include many different materials. The materialselected must be one which is compatible with the composition ofinterest and does not excessively abrade dentin. Suitable abrasivesinclude, for example, silicas including gels and precipitates, fusedsilica, insoluble sodium polymetaphosphate, hydrated alumina, andresinous abrasive materials such as particulate condensation products ofurea and formaldehyde.

Silica dental abrasives of various types are preferred herein because oftheir unique benefits of exceptional dental cleaning and polishingperformance without unduly abrading tooth enamel or dentine. Silicaabrasive polishing materials herein, as well as other abrasives,generally have an average particle size ranging from 0.1 to 30 μm, andpreferably from 5 to 15 μm. The abrasive can be precipitated silica orsilica gels such as the silica xerogels marketed under the trade name“Syloid” by the W.R. Grace & Company, Davison Chemical Division andprecipitated silica materials such as those marketed by the J.M. HuberCorporation under the trade name, Zeodent®, particularly the silicascarrying the designation Zeodent® 119, Zeodent® 118, Zeodent® 109 andZeodent® 129. The types of silica dental abrasives useful in thetoothpastes of the present invention are described in more detail inU.S. Pat. Nos. 4,340,583; 5,603,920; 5,589,160; 5,658,553; 5,651,958;and 6,740,311.

Alternatively, mixtures of dental abrasives can be used, such asmixtures of the various grades of Zeodent® silica abrasives as listedabove, or mixtures of the silica abrasives and calcium-containingabrasives. Dental solution, mouth spray, mouth wash, and non-abrasivegel compositions of the subject invention typically contain little or noabrasive.

Sweetener

The oral care compositions herein may include a sweetening agent. Theseinclude sweeteners such as saccharin, dextrose, sucrose, lactose,xylitol, maltose, levulose, aspartame, sodium cyclamate, D-tryptophan,dihydrochalcones, acesulfame, sucralose, neotame, and mixtures thereof.Sweetening agents are generally used in oral care compositions at levelsof from 0.005% to 5%, alternatively 0.01% to 1%, by weight of thecomposition, alternatively from 0.1% to 0.5%, alternatively combinationsthereof.

Fluoride Ion Source

The oral care active may include an effective amount of an anti-cariesagent. In one embodiment, the anti-caries agent is a fluoride ionsource. The fluoride ion may be present in an amount sufficient to givea fluoride ion concentration in the composition at 25° C., and/or in oneembodiment can be used at levels of from 0.0025% to 5% by weight of thecomposition, alternatively from 0.005% to 2.0% by weight of thecomposition, to provide anti-caries effectiveness. Examples of suitablefluoride ion-yielding materials are disclosed in U.S. Pat. Nos.3,535,421, and 3,678,154.

Representative fluoride ion sources include: stannous fluoride, sodiumfluoride, potassium fluoride, amine fluoride, sodiummonofluorophosphate, zinc fluoride, and mixtures thereof. In oneembodiment the oral care composition contains a fluoride source selectedfrom stannous fluoride, sodium fluoride, and mixtures thereof. In onembodiment, the fluoride ion source is sodium monofluorophosphate, andwherein the composition comprises 0.0025% to 2% of the sodiummonofluorophosphate by weight of the composition, alternatively from0.5% to 1.5%, alternatively from 0.6% to 1.7%, alternativelycombinations thereof. In another embodiment, the composition comprisesfrom 0.0025% to 2% of a fluoride ion source by weight of thecomposition.

Anti-Calculus Agent

The oral care compositions may include an effective amount of ananti-calculus agent, which in one embodiment may be present from 0.05%to 50%, alternatively from 0.75% to 25%, alternatively from 0.1% to 15%.Non-limiting examples include those described in U.S. Publication No.2011/0104081A1 at paragraph 64, and those described in U.S. PublicationNo. 2012/0014883A1 at paragraphs 63 to 68, as well as the referencescited therein. One example is a pyrophosphate salt as a source ofpyrophosphate ion. In one embodiment, the composition comprisestetrasodium pyrophosphate (TSPP) or disodium pyrophosphate orcombinations thereof, preferably 0.01% to 2%, more preferably from 0.1%to 1% of the pyrophosphate salt by weight of the composition. Withoutwishing to be bound by theory, TSPP may provide not only calciumchelating thereby mitigating plaque formation, but also may also providethe additional benefit of monofluorophosphate stabilization (in thoseformulations containing monofluorophosphate).

Surfactant

The compositions herein may include a surfactant. The surfactant may beselected from anionic, nonionic, amphoteric, zwitterionic, cationic,betaine surfactants, or mixtures thereof. The oral care composition mayinclude a surfactant at a level of from about 0.1% to about 50%, fromabout 0.025% to about 9%, from about 0.05% to about 5%, from about 0.1%to about 2.5%, from about 0.5% to about 2%, or from about 0.1% to about1% by weight of the total composition. Non-limiting examples of anionicsurfactants may include those described at US 2012/0082630 A1 atparagraphs 32, 33, 34, and 35. Non-limiting examples of zwitterionic oramphoteric surfactants may include those described at US 2012/0082630 A1at paragraph 36; cationic surfactants may include those described atparagraphs 37 of the reference; and nonionic surfactants may includethose described at paragraph 38 of the reference.

Humectants

The oral care compositions herein may contain humectants. The humectantsserves to keep the oral care composition from hardening upon exposure toair, to give a moist feel to the mouth, and, for particular humectants,to impart a desirable sweetness of flavor.

Suitable humectants for the present invention include edible polyhydricalcohols such as glycerin, sorbitol, xylitol, butylene glycol,polyethylene glycol, propylene glycol, and combinations thereof. In oneembodiment, the humectant is selected from sorbitol, glycerin, andcombinations thereof. In yet another embodiment, the humectants issorbitol. In one embodiment, the oral care composition comprises from20% to less than 80% of humectants by weight of the composition,preferably from 30% to 50%. In yet another embodiment, the oral carecomposition contains 30% to 50% of sorbitol by weight of the oral carecomposition.

Coloring Agents

The oral care compositions herein may include a coloring agent (i.e.,pigments, dyes and opacifiers). The coloring agent may be in the form ofan aqueous solution, preferably 1% coloring agent in a solution ofwater. Titanium dioxide may also be added to the present composition.Titanium dioxide is a white powder which adds opacity to the oral carecompositions. Titanium dioxide generally comprises from about 0.25% toabout 5%, by weight of the oral care composition.

Flavorant

The oral care compositions herein may include from about 0.001% to about5%, alternatively from about 0.01% to about 4%, alternatively from about0.1% to about 3%, alternatively from about 0.5% to about 2%,alternatively combination thereof, of a flavorant composition by weightof the oral care composition. The term flavorant composition is used inthe broadest sense to include flavor ingredients, or sensates, orsensate agents, or combinations thereof. Flavor ingredients may includethose described in U.S. Publication No. 2012/0082630A1 at paragraph 39;and sensates and sensate ingredients may include those described atparagraphs 40-45, incorporated herein by reference.

Examples of flavor compositions or flavor ingredients include: mintoils, wintergreen, clove bud oil, cassia, sage, parsley oil, marjoram,lemon, orange, propenyl guaethol, heliotropine, 4-cis-heptenal,diacetyl, methyl-p-tert-butyl phenyl acetate, methyl salicylate, ethylsalicylate, 1-menthyl acetate, oxanone, a-irisone, methyl cinnamate,ethyl cinnamate, butyl cinnamate, ethyl butyrate, ethyl acetate, methylanthranilate, iso-amyl acetate, iso-amyl butyrate, allyl caproate,eugenol, eucalyptol, thymol, cinnamic alcohol, octanol, octanal,decanol, decanal, phenylethyl alcohol, benzyl alcohol, a-terpineol,linalool, limonene, citral, neral, geranial, geraniol nerol, maltol,ethyl maltol, anethole, dihydroanethole, carvone, menthone,beta-damascenone, ionone, gamma-decalactone, gamma-nonalactone,y-undecalactone, or combinations thereof. Generally suitable flavoringredients are chemicals with structural features and functional groupsthat are less prone to redox reactions. These include derivatives offlavor ingredients that are saturated or contain stable aromatic ringsor ester groups.

Sensates such as cooling, warming, and tingling agents are useful todeliver signals to the consumer. The most well-known cooling agent ismenthol, particularly 1-menthol, which is found naturally in peppermintoil. Among synthetic cooling agents, many are derivatives of or arestructurally related to menthol, i.e., containing the cyclohexanemoiety, and derivatized with functional groups including carboxamide,ketal, ester, ether and alcohol. Examples include thep-menthanecarboxamide compounds such as N-ethyl-p-menthan-3-carboxamide(known commercially as “WS-3”). An example of a synthetic carboxamidecooling agent that is structurally unrelated to menthol isN,2,3-trimethyl-2-isopropylbutanamide. Additional exemplary syntheticcooling agents include alcohol derivatives such as3-1-menthoxy-propane-1,2-diol, isopulegol, p-menthane-3,8-diol; menthoneglycerine acetal (known commercially as “MGA”); menthyl esters such asmenthyl acetate, menthyl acetoacetate, menthyl lactate, and monomenthylsuccinate.

Additional agents that are structurally unrelated to menthol but havebeen reported to have a similar physiological cooling effect includealpha-keto enamine derivatives described in U.S. Pat. No. 6,592,884,including 3-methyl-2-(1-pyrrolidinyl)-2-cyclopenten-1-one (3-MPC),5-methyl-2-(1-pyrrolidinyl)-2-cyclopenten-1-one (5-MPC);2,5-dimethyl-4-(1-pyrrolidinyl)-3 (2H)-furanone (DMPF); icilin (alsoknown as AG-3-5, chemical name142-hydroxyphenyl]-4-[2-nitrophenyl]-1,2,3,6-tetrahydropyrimidine-2-one).

Some examples of warming agents include ethanol; nicotinate esters, suchas benzyl nicotinate; polyhydric alcohols; nonanoyl vanillyl amide;nonanoic acid vanillyl ether; vanillyl alcohol alkyl ether derivativessuch as vanillyl ethyl ether, vanillyl butyl ether, vanillyl pentylether, and vanillyl hexyl ether; isovanillyl alcohol alkyl ethers;ethylvanillyl alcohol alkyl ethers; veratryl alcohol derivatives;substituted benzyl alcohol derivatives; substituted benzyl alcohol alkylethers; vanillin propylene glycol acetal; ethylvanillin propylene glycolacetal; ginger extract; ginger oil; gingerol; zingerone; or combinationsthereof.

Examples of some tingling agents include capsaicin; homocapsaicin, jambuoleoresin, zanthoxylum peperitum, saanshool-I, saanshool II,sanshoamide, piperine, piperidine, spilanthol,4-(1-methoxymethyl)-2-phenyl-1,3-dioxolane, or combinations thereof.

The oral care compositions herein can further include herbal ingredientssuch as extracts of chamomile, oak bark, Melissa, rosemary and salvia.These, and some of the herb-derived flavoring components can be includedat levels just sufficient to provide a contribution to the flavor orthey can be added at higher levels, such as 1% or more, in order toprovide a greater therapeutic effect.

Other suitable flavorant components are described in Fenaroli's Handbookof Flavor Ingredients, Third Edition, Volumes 1 & 2, CRC Press, Inc.(1995), and Steffen Arctander's Perfume and Flavour Chemicals, Volumes 1& 2 (1969).

Other Ingredients

The present oral care composition can comprise the usual andconventional ancillary components such as anti-microbial agents,fluoride ions, and other ingredients that are known to one skilled inthe art. It will be appreciated that selected components for the oralcare compositions must be chemically and physically compatible with oneanother.

Method of Use

The present invention also relates to methods for treating the oralcavity comprising administering to the oral care cavity an oral carecomposition according to the present invention. In an embodiment, theterm “treating” refers to cleaning and polishing teeth. The method ofuse herein comprises contacting a subject's dental enamel surfaces andoral mucosa with the oral care compositions according to the presentinvention. The method of treatment may be by brushing with a dentifriceor rinsing with a dentifrice slurry or mouthrinse. Other methods includecontacting the topical oral gel, mouthspray, toothpaste, dentifrice,tooth gel, tooth powders, tablets, subgingival gel, foam, mouse, chewinggum, lipstick, sponge, floss, petrolatum gel, or denture product orother form with the subject's teeth and oral mucosa. Depending on theembodiment, the oral care composition may be used as frequently astoothpaste, or may be used less often, for example, weekly, or used by aprofessional in the form of a prophy paste or other intensive treatment.

Test Methods

It is understood that the assays disclosed in the Test Methods sectionof the present application must be used to determine the respectivevalues of the parameters of the present invention, as such an inventionis described and claimed herein.

1. Tip Viscosity Assay

This assay is used to measure the viscosity of the oral care compositionnear the tip of the dispenser in which it is contained (also referred toas ‘Tip Viscosity’). The Tip Viscosity is relevant to the determinationof phase stability property of a formulation over time. According tothis method, the Tip Viscosity of the oral care compositions can bemeasured via a control rate model using a Thermo HAAKE MARS RotationalRheometer with spindle and a 20 mm diameter parallel-plate with thefollowing parameters: a gap of approximately 1.0 mm, shear rates of 0.1l/s to 100 l/s, at temperature of 25° C. The details of the method areas follows:

Sample Preparation:

Samples of the oral care composition are prepared as follows.

-   1. Pack about 90 grams of the composition into a 180 grams    transparent plastic laminate tube having a diameter of 38 mm and a    height of 177.5 mm, and seal the opening (i.e., tail).-   2. Place the tube in the vertical position with the tail positioned    up and incubate the samples at 40° C. for varying duration (e.g., 0,    1 month, 2 months, 3 months, 4.5 months, etc.). The Tip Viscosity    measurement is based on the average of tripilicate tubes for each    sampling time point.-   3.

Measurement:

-   4. After the incubation, use scissors to cut the tube near the    middle to give approximately equal halves (i.e., upper & lower    portions of the tube). Try to avoid touching the packed composition    in the upper portion of the tube.-   5. Use a spatula to load about 0.4 g of the packed composition from    the upper portion of the tube onto the bottom plate of the    Rheometer.-   6. Lift the upper plate to standby position at 6.000 mm, then lift    the upper plate to position at 1.040 mm in 60 secs.-   7. Trim samples of the oral care composition with plastic strip and    attach the anti-evaporation cap.-   8. Lift the upper plate to measuring position at 1.000 mm and re-set    the normal force. Set the temperature at 25° C., then standby at    25° C. for 300 secs.-   9. Continuous rotation ramp measurement recorded using control rate    model with parameters: shear rate from 0.1 l/s to 100 l/s; data    point 150 with log distribution; test duration 300 secs.-   10. Record Tip Viscosity result at shear rate of 1 s⁻¹ as integer.

EXAMPLES

The following examples and descriptions further clarify embodimentswithin the scope of the present invention. These examples are givensolely for the purpose of illustration and are not to be construed aslimitations of the present invention as many variations thereof arepossible without departing from the spirit and scope.

Example 1

Toothpaste compositions according to the present invention (“PresentInvention Sample 1”) and a comparative formulation (“Comparative Sample1”) are shown below with amounts of components in wt %. Thesecompositions are made using conventional methods.

TABLE 1 Oral Care Formulations Amount (Wt %) Present InventionComparative Ingredients Sample 1 Sample 1 Stannous Chloride 1.16 1.16Phytic Acid — 0.8 Sorbitol 48.0 38.07 Sodium Carboxymethyl Cellulose —1.3 Carrageenan 1.5 0.7 Xanthan Gum 0.88 — Hydroxyethyl Cellulose — 0.5Water and minors (e.g., color soln.) q.s. q.s. Target pH 6 6

Example 2 Phase Stability

In order to determine phase stability over a period time for the oralcare composition of the present invention, a Tip Viscosity assay wascarried out which compared a sample composition with carrageenan, andxanthan gum (but no CMC) versus a comparative formulation containingcarrageenan, hydroxyethyl cellulose and CMC (but no xanthan gum). TipViscosity was measured for the formulations from time 0 to 5 monthsstored at 40° C. As shown in FIG. 2, the Tip Viscosity for theComparative Sample drops quickly after 1 month while the Sample 1composition of the present invention remains relative consistent up to4.5 months. Additionally, the Sample 1 composition also shows no visualphase separation by 4.5 months.

Example 3 Toothpaste Formulations

The following examples in Table 2 further describe and demonstrate theuse of the present invention within toothpaste embodiments. Theseexamples are given solely for the purpose of illustration and are not tobe construed as limitations of the present invention as many variationsthereof are possible. Toothpaste compositions are shown below withamounts of components in weight %. These compositions are made usingconventional methods.

TABLE 2 Toothpaste Formulations Example A Example B Example C Example DIngredient (wt %) (wt %) (wt %) (wt %) Sorbitol sol. (70%) 48.000 48.000  38.000  48.000  Sodium Fluoride 0.321 0.210 0.321 — Zinc Citrate— 0.533 0.533 — Zinc Lactate Dihydrate 1.850 — — 1.070 Stannous ChlorideDihydrate 1.160 1.160 1.160 0.510 Stannous Fluoride — — — 0.454 NaGluconate 1.064 1.064 1.064 1.064 Xanthan Gum 0.875 0.300 1.000 0.875Carrageenan 1.500 1.500 0.65  1.500 Silica Abrasive 16.000  20.000 17.000  16.000  Sodium Lauryl Sulfate 7.000 5.000 7.500 7.000 (28%soln.) Na Saccharin 0.300 0.300 0.250 0.300 Flavor 1.100 1.000 1.3001.100 Na Hydroxide (50%) 0.980 0.980 0.900 0.650 Water and minors q.s.q.s. q.s. q.s (e.g. color soln.) Target pH 6.0  6.0  6.0  6.0 

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

Every document cited herein, including any cross referenced or relatedpatent or application and any patent application or patent to which thisapplication claims priority or benefit thereof, is hereby incorporatedherein by reference in its entirety unless expressly excluded orotherwise limited. The citation of any document is not an admission thatit is prior art with respect to any invention disclosed or claimedherein or that it alone, or in any combination with any other referenceor references, teaches, suggests or discloses any such invention.Further, to the extent that any meaning or definition of a term in thisdocument conflicts with any meaning or definition of the same term in adocument incorporated by reference, the meaning or definition assignedto that term in this document shall govern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. An oral care composition comprising: a. from0.01% to 2% by weight of a stannous chloride source; b. a thickeningagent consisting of: i) from 1% to 5% by weight carrageenan; and ii)from 0.3% to 0.875% by weight xanthan gum; c. at least 30% by weight ofa total water content; and d. from 20% to 80% of a humectant selectedfrom the group consisting of glycerin, sorbitol, xylitol, butyleneglycol, polyethylene glycol, propylene glycol, and combinations thereof;e. a dental abrasive consisting of precipitated silica; f. from 0.01% to2% by weight of a fluoride ion source; wherein the composition has a pHof greater than 4 and comprises less than 0.001% of a charged cellulosederivative having greater than 0.5 charged groups per sugar residue unitalong the polysaccharide backbone; wherein the composition has a TipViscosity of greater than 100 Pa·s after 4.5 months at 40° C.; whereinthe xanthan gum has a degree of substitution of less than 0.4carboxylate groups per sugar residue.
 2. The oral care compositionaccording to claim 1, wherein the charged cellulose derivative iscarboxymethyl cellulose (CMC).
 3. The oral care composition according toclaim 1, wherein the stannous chloride is selected from the groupconsisting of stannous chloride dehydrate, stannous chloride anhydrous,and combinations thereof.
 4. The oral care composition according toclaim 1, wherein the carrageenan is present in the amount of from 0.7%to 2% by weight.
 5. The oral care composition according to claim 4,wherein the carrageenan is selected from the group consisting ofKappa-carrageenan, Iota-carrageenan, Lambda carrageenan, andcombinations thereof.
 6. The oral care composition according to claim 5,wherein the carrageenan is Iota-carrageenan.
 7. The oral carecomposition according to claim 1, wherein the pH is between 4.5 and 9.5.8. The oral care composition according to any claim 7, wherein the pH isbetween 5 and
 7. 9. The oral care composition according to claim 1,wherein the total water content is between 30% to 60% by weight.
 10. Theoral care composition according to claim 1, further comprising 0.1% to10% by weight of a chelant.
 11. The oral care composition according toclaim 10, wherein the chelant is selected from the group consisting of alactate, citrate, gluconate, and combinations thereof.
 12. The oral carecomposition according to claim 1, wherein the Tip Viscosity does notsubstantially decrease after 4 months at 25° C.
 13. A method fortreating the oral cavity comprising administering to the oral cavity anoral care composition according to claim
 1. 14. An oral care compositioncomprising: a. from 0.01% to 2% by weight of stannous chloride; b. athickening agent consisting of: i) from 1.25% to 3% by weightcarrageenan; and ii) from 0.3% to 0.875% by weight xanthan gum; c. atleast 30% by weight of a total water content; and d. from 20% to 80% ofa humectant selected from the group consisting of glycerin, sorbitol,xylitol, butylene glycol, polyethylene glycol, propylene glycol, andcombinations thereof; e. a dental abrasive consisting of precipitatedsilica; f. from 0.01% to 2% by weight of stannous fluoride; wherein thecomposition has a pH of greater than 4 and comprises less than 0.001% ofa charged cellulose derivative having greater than 0.5 charged groupsper sugar residue unit along the polysaccharide backbone.